Assessing the impact of coastal processes on archaeological sites in Loíza Puerto Rico: integrating Geographic Information System (GIS), remote sensing, and numerical modeling techniques

Abstract

Archaeological sites are a part of cultural heritage that is threatened by accelerated climate change. This research evaluated climate hazard impacts on archaeological sites in Loíza, Puerto Rico. The main methods applied to understand these threats to archaeological sites were fieldwork, data collection, geographic information systems, remote sensing, statistics, and numerical modeling. Using the Digital Shoreline Analysis System, an analysis of shoreline changes was conducted from 1902 to 2108 to establish the proximity of archaeological sites to erosional areas and to estimate when these sites may be impacted in the future by shoreline recession. The archaeological sites’ spatial intersections with threats such as sea-level rise projections (1-ft to 3-ft), storm surges, high tide flooding, and FEMA zones were evaluated. A total physical vulnerability value was then calculated using these threats and a prioritization ranking value, using the Scottish Coastal Archaeology and the Problem of Erosion approach, was assigned to each archaeological site based on its significance and physical vulnerability value. Due to the complexity of the coast of Puerto Rico and Loíza, the numerical models CMS-Wave and Flow were used to understand morphological changes due to wave energy, wind, and bathymetry.<br /> <br />Findings indicated that eight Loíza sites are vulnerable to shoreline recession within 100 years, and 15 sites could be vulnerable within 100 to 500 years. The majority of the sites (16) are vulnerable to four hazards: FEMA V Zones (1%) and A Zones (1% and 0.2%), and tsunami run up zones. Four sites are vulnerable to 10 hazards: FEMA A Zones (1% and 0.2%), shallow coastal flooding, sea level rise (1-ft, 2-ft, and 3-ft), storm surges (Hurricane Categories 1, 2, and 3), and tsunami run up zones. For sea level rise scenarios, 13 sites will be vulnerable by 2050, 2070, or 2090. Furthermore, the results regarding morphological changes showed that archaeological sites such as LO-27 Playa Berwind in Punta Uvero were near erosional areas in the bottom.<br /> <br />The final prioritization value for management purposes showed that most of the sites obtained a high priority (45%), followed by medium priority (40%), and low priority (15%). Cueva de los Indios and Parroquia Espíritu Santo y San Patricio, archaeological sites registered in the National Register of Historic Places, obtained high and medium priority values, respectively. These priority values indicate the urgency that should be given to archaeological sites for management purposes.<br /> <br />This research is significant because it presents new methods for evaluating possible accelerated climate change hazards to archaeological sites in Loíza, Puerto Rico. In addition, it provides new data regarding shoreline changes and morphological changes for the sites, which may also be used for coastal management and planning processes.